Comparison of the shaping characteristics of Neolix and Protaper Universal systems in preparation of severely-curved simulated canals

BACKGROUND The aim of this in vitro study was to compare the shaping characteristics of two types of nickel-titanium endodontic file systems with regard to the following parameters: Canal straightening, Canal deviation and Instrumentation time. MATERIAL AND METHODS Fifty severely curved canals simulated in resin blocks were prepared to an apical size 25 using Protaper Universal orNeolix systems (n=25 canals/group). The angle of canal curvature was determined before and after instrumentation. Pre- and post-operative images were superimposed to determine any canal deviation. The instrumentation time was also recorded. The data were statistically analyzed by using independent sample t-test and the Mann-Whitney U-test. RESULTS There were no significant differences between the groups in terms of the change in canal angle (P > 0.05). The Neolix system produced less canal deviation at 7 of the 12 measuring points (p<0.05). The Neolix system also required less instrumentation time (p<0.05). CONCLUSIONS Both rotary systems were capable of maintaining the original curvature of the root canal; however, the Neolix system resulted in less canal deviation as well as shorter instrumentation time. Key words:Apical foramen,canal transportation, nickel-titanium instruments, Protaper Universal, root canal preparation.